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90 Cards in this Set
- Front
- Back
THINGS TO REMEMBER IN ANALYTICAL METHOD |
Principle of the method Purpose of the method Distinguishing Characteristic of the test |
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Visible spectrum |
400-700nm |
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Ultraviolet region (UV) |
<400nm |
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Infrared Region (IR) |
>700nm |
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Number of vibrations of wave per second |
Frequency |
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Represents the wavelenght in nanometers at peak transmittance |
Nominal wavelenght |
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Wavelenght indicated on the control dial and is the actual wavelenght of light passed by the monochromator |
wavelenght accuracy |
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Used to check wavelength accuracy (wavelenght calibration) |
Didymium or holmium oxide filter |
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Verify absorbance accuracy on linearity |
Neutral density filters and dicromate solution |
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Involves measurement of the light transmitted by a solution to determine the concentration of the light-absorbing substances in the solution. |
Spectrophotometry |
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Simplest type of absorption spectometer, designed to make one measurement at a time at one specific wave lenght. |
Single Beam spectrophotometer |
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Part of spectrophotometer Provides polychromatic light and must generate sufficient radiant energy or power to measure the analyte of interest. |
Light/Radiant Source |
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Commonly used light source in spectrophotometer |
Tungsten light bulbs |
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Routineline used to provide UV radiation innanalytic spectrophotometers. |
Deuterium lamp |
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Minimize unwanted or stray light and prevents the entrance of scattered light into the monochromator system. |
Entrance slit |
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Unwanted light inside the spectrophotometer |
Stray light |
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Most common cause of loss of linearity at high analytr concentration |
Stray light |
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Causes absorbance error |
Stray light |
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Isolate specific or individual wavelenght of light |
Monochromator |
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Wedge-shaped piecew of glass, quartz or sodium chloride |
Prisms |
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most commonly used monochromator |
Diffraction gratings |
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Filters stray light and specific light |
Sharp-cut off filter |
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Simple , least expensive not precise but useful. |
Filters |
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Controls width of the light beam (bandpass)- allows only a narrow fraction of the spectrum to reach the sample cuvette |
Exit slit |
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Is the total range of wavelengths transmitted |
Bandpass |
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Also called absorption cell/analytical cell/sample cell |
cuvet |
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Most commonly used cuvet (can be used in 350-2000nm) |
Alumina silica glass |
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Used for measurement of solution requiring visible and ultraviolet spectra |
Quartz/plastic |
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detects and converts transmitted light into photoelectric energy |
Photodetector |
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Simpliest detector, least expensive; temperature-sensitive |
Barrier layer cell/ Photocell/ photovoltaic cell |
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used to filter photometers with wide band pass |
Barrier layer cell/ Photocell/ photovoltaic cell |
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kinds of detectors |
Barrier layer cell/ Photocell/ photovoltaic cell
phototube
photomultiplier tube (PMT) photodiode |
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Most sensitive detector and most commlnly used. |
Photomultiplier tube (PMT) |
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displays output of the detection system |
meter or read out device |
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Formula for absorbance |
A= abc = 2-log%T A= absorbance a= molar absorptivity b= lenght of light through the solution c= concentration of absorbig molecules/solution |
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Fomula for percent transmittance |
%T= It/Io x 100 It = trasmitted light thru the sample Io = intensity of light striking the sample |
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Flame Emission Photometry |
- Measures the light emitted by a single atom burned in a flame Principle : Excitation of electrons from lower to higher energy state Light source: Flame Used to measure excited ion (sodium and potassium |
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Atomic Absorption Spectrophotometry (AAS) |
Principle: Element is not dissociated but by heat energy from its chemical bonds. Light Source: Hallow-cathod lamp Used for measurement of unexcited trace metals (calcium and magnesium) |
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Reference method for measurement of Magnesium |
AAS |
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Volumetric (Titrimetric) |
Principle: unknown sample is made to react with a known solution in the presence of an indicator |
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Turbidimetry |
Principle : Amount of light blocked (reducing of light) Measuring abundant large particles (proteins) |
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In turbidimetry an increase in concentration means? |
Increase turbidity |
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What is the analyte that uses turbidimetry because they are abundant in the serum plasma and whole blood, they also have large particle. |
Serum protein |
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2 distinct test for Proteins |
Turbidimetry Nephelometry |
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Nephelometry |
Principle : Determines amount of scattered light in a turibid soluiton Measuring amount of antigen-antibody complexes (protein) Measurement of gamma globulins |
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Electrophoresis |
Principle : migration of charged particles in an electric field Most important initial test for the identification and differentiation of isoenzyme |
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Buffer for electrophoresis |
Barbital a.k.a Veronal |
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Has a net charge that can be either positive or negative depending on pH conditions |
Amphoteric |
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Factors affecting rate of migration |
Net electric charge of the molecule Size and shape of the molecule Electric field strength Nature of the supporting medium Temperature of operation |
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Supporting Media for Electrophoresis |
Cellulose acetate Agarose gel Polyacrylamide Gel |
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Supporting Media for electrophoresis that separates molecular size and is commonly used in SPE. |
Cellulose acetate |
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Separates by electrical charge; it does not bind protein |
Agarose gel |
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Best supporting media in electrophoresis and it is used to study isoenzymes |
Polyacrylamide Gel |
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Fastest migrating protein in electrophoresis |
Albumin |
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Slowest migrating protein in electrophoresi |
Gamma globulin |
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Normal SPE |
5 bonds ( 1 albumin , 4 globulins ) |
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Stains for protein and enzymes |
Amido black Ponceus S |
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Stains for Lipoprotein |
Sudan Black Oil Red O Fat Red 7B |
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Stain for CSF protein |
Coomassie Blue |
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Measures the absorbance of stain concentration of the dye and protein fraction. It scans and quantitates electrophoresis pattern |
Densitometry |
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Separation of soluble components in a solution by a specific differences in physical-chemical characteristics of the different constituents |
Chromatography |
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Semiquantitative drug screening test |
TLC (thin layer chromatography) |
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Only test that has Rf value |
TLC |
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Used for separation of steroids, barbiturates, blood, alcohol, and lipids. |
Gas Chromatography (GC) |
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Based on the fragmentation and ionization of molecules using a suitable source of energy. |
Mass spectroscopy |
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What is the most specific and sensitive method used in drug testing? |
GC-MS |
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Which between GC and MS is responsible for identification of the drug whether therapeutic or illicit present on the sample? |
Mass spectroscopy |
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Gold standard for Drug testing |
GC-MS |
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Used for therapeutic drug monitoring and drug testing |
GC-MS |
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Based on the distribution of solutes between a liquid mobile phase and a stationary phase |
Liquid Chromatography |
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Complementary method to GC-MS |
LC-MS (liquid chromatography- MS) |
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Fluorometry/Molecular Luminescence Spectrophotometry |
Principle : determines amount of light emitted by a molecule after excitation by electromagnetic radiation Use: porphyrins, magnesium, Calcium, and cathecolamines Measures amount of light intensity present over a zero backgorund |
|
Is the difference between the maximum wavelength, excitation, and emitted fluorescence |
Stoke Effect |
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2 monochromators for Fluorometry |
Primary monochromator (excitation monochromator) >Selects wavelength- isolates specific light Secondary monochromator (emission monochromator) > prevents incident light ( stray light) |
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Chemiluminescence |
Measurement of light signal is against a dark background since no excitation of light is required Has no monochromator |
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ELECTROCHEMISTRY TECHNIQUES |
Potentiometry Coulometry Amperometry Voltammetry |
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Measurement of current or voltage generated by the activity of a specific ion |
Electrochemistry techniques |
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Measure blood pH, blood gasses, glucose, ionize calcium, lead, and chloride |
Electrochemistry techniques |
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Measurement of PCO2 |
Potentiometry |
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Nernst equation |
Potentiometry |
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Potentiometry |
Measurement of differences in voltage (potential) at constant current Reference electrode: Calomel (internal) and silver-silver chloride (external), glass pH electrode Use: pH and PCO2 , electrolytes |
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Instrument use in potentiometry |
Ion Selective Electrode (ISE) |
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Measurement of the amount of electricity at fixed |
Coulometry |
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Faraday's law |
Coulometry |
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Chloride test |
Coulometry |
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Amperometry |
Measurement of current flow produce by an oxidation-reaction |
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Measures pO2 and Glucose |
Polarography |
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Ilkovic equation |
Polarography |
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Measurement of current after which a potential is applied to an electrochemical cell |
Voltammetry |
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Measures heavy metals such as lead |
Anodic stripping voltametry |